Do you know of an independent test lab that can measure APHA/Pt-Co/Hazen Color?

Contact the following and ask for “APHA/Pt-Co/Hazen Color testing per ASTM D1209 and D5386″.

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Can HunterLab instruments measure APHA/Pt-Co/Hazen Color above 500?

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ASTM Industrial Test Methods for visual and instrumental APHA Color Scale

FAQ: “Does HunterLab have any documentation to show that the UltraScan VIS is compliant with ASTM 1209. One of our customers is having a problem regarding the method. Their client is using the manual visual method for performing the ASTM 1209 color test method whereas they use the UltraScan VIS. Can you explain the difference?” Continue reading

References for Hazen Color Scale

The original references were written by Allen Hazen, a chemist who first defined APHA/Pt-Co/Hazen color scale for the evaluation of water quality on behalf of the American Public Health Association:

Hazen, A. A new color standard for natural waters, American Chemist Journal (14:300), 1892.

Hazen, A. The measurement of the colors of natural waters, American Chemist Journal (18:264), 1896.


Industrial Test Methods referencing the Hazen Color Scale

ISO 2211:1973 Liquid chemical products – Measurement of colour in Hazen units (platinum cobalt scale) is an ISO method that references both Hazen and platinum cobalt color and was subsequently replaced by DIN EN ISO 6271.


History of the APHA/Pt-Co/Hazen Color Scale
PtCo Std Bottles
Bottles of APHA/Pt-Co/Hazen 500 color standard.

“APHA” stands for American Public Health Association Color Scale, the organization responsible for the original definition and implementation of this visual color scale as a standard method for rating water quality. Continue reading

APHA/Pt-Co/Hazen vs Gardner color scales: What’s the difference?

The APHA/Pt-Co/Hazen and Gardner visual color scales were both originally based on liquid chloroplatinate color standards but have different history and intended use. Continue reading

What Path Length Cell should I use for APHA/Pt-Co/Hazen Color Measurement?

FAQ: ” We are currently using a 10 mm path length and read in the 0 – 50 region for APHA/Pt-Co/Hazen Color, usually in the area of 10. Would you recommend a 10 mm path length with our equipment for this application?” Continue reading